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  1. #21
    Join Date
    Dec 2005
    Location
    Volga, SD
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    2,791

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    i dont think anyone can equal the selective pressure of II with selecting the best performing colony. -josethayil
    Want to bet? I think it can be done pretty easily.

    Let's say that I decide I only want cordovan bees. Any colony that has any offspring that do not express cordovan traits gets destroyed immediately by me (my selective program). I do nothing else, no II, nothing. How great is that selective pressure? Is it as great as the selective pressure on my bees if I were to II them and not destroy those that meet my strict expectations?

    Don't confuse "efficiency of method of selective breeding" with "selective pressure." The two do differ.

    natural selection gives a hive all its optons available to survive. -josethayil
    Not exactly. Selection, natural or artificial, removes those that are not adapted to match the selective pressure.

    Selective forces are also responsible for extinction.

    In US there were only a few hives brought initially and everytime a queen or hive was imported it has gone through human selection which does reduce the gene pool. -josethayil
    More bees were imported into the U. S. than were imported into eastern Russia. And the bees imported into the U. S. represent Apis mellifera mellifera, A. m. liguistica, A. m. carnica, A. m. caucasica, A. m. scutellata , and Buckfast bees (which are a hybrid of any number of subspecies from around the world), and more. That range of subspecies, even allowing for only a few lines of each, represents a far greater range of genes than the limited number of hives taken to eastern Russia. Oh, and descendents of those bees taken to Primorsky Krai have since been imported into the U. S. and widely distributed by humans here. So, those genes are available here.

    Don't confuse "genetic diversity," with "phenotypes worth conserving." Some of the most unique phenotypes, maybe some of those most worth conserving, are actually the result of limited genetic diversity.

    Natural selection always preserves as mmuch genetics as possible. . . -josethayil
    Not so. Natural selection does no such thing. Natural selection tends to eliminate genes (genetics) in favor of those few that are most evolutionarily fit.

    Natural selection can act very, very rapidly. Natural selection can also be responsible for extinctions (which clearly do not preserve genetics), and natural selection can be more or less efficient than "human selection." The strength of the selective pressure is key here. Think of it in terms of human selection: if you aren't completely ruthless in selecting breeding characteristics, the selective pressure that you're putting on your bees isn't as great, and isn't likely to act as rapidly or as completely as if you are completely ruthless. Strength of natural selection can vary, too, from weak pressures to extremely strong pressures.

  2. #22
    Join Date
    Jul 2008
    Location
    hamilton city, new zealand
    Posts
    169

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    Alright.

    After you have answered all those questions, let me ask something else.

    Why did the US have to import The russian bees for varroa resistance, When the US had all these different races and high level of gene pool available as you explain, and a lot of experienced queen breeders and all in such a vast country?

    If any one could have done what nature can do it would have been done a lot earlier. I remember that even the US had varroa for a long period of time now and still with all the advanced technology and research going on, we still dont have a Self sustaianable population of Varroa resistant bees in the US.

    According to me a single strain of bees which has gone through only natural selection has a vast gene pool and is better than a lot of different strains of bees brought together with reduced gene poool to work with.

    What I am saying is a 100 hives of bees which has not touched by humans can have a better gene pool in them that a 1000 hives which has gone through II and slective queen breeding.

  3. #23
    Join Date
    Dec 2005
    Location
    Volga, SD
    Posts
    2,791

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    I believe you're confusing "vast gene pool" with "phenotype suited to a particular situation."

    The broadest range of genes is not necessarily what beekeepers strive for, and is certainly not what nature selects. Natural selection necessarily reduces genetic diversity (the "gene pool"). Artificial selection necessarily reduces genetic diversity.

    Let's see if I can make it more clear: we start with a broad "gene pool." We have bees with genes that do this, do that, do the next thing. Some of those genes do not confer any Varroa tolerance. If those bees are left to "nature" and have to survive Varroa, all the genes that are not capable of withstanding the mites will be eliminated. That diversity is gone, the "gene pool" has been reduced. Same if humans only select bees with that trait. Using chemical treatments preserves the genetic diversity (large "gene pool"), but is that desireable?

    "Genetic diversity" should not necessarily be equated with "good," just like "natural selection" should not be equated with "suits the ideals of humans."

    Sure, 100 unmanaged hives can have greater genetic diversity than 1000 hives managed through II and intense selection. I still maintain that one subspecies inherently has less diversity than a population created by combining several subspecies of that same species. Remember, differences among subspecies are greater than within subspecies.

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